Republican presidential challenger Mitt Romney edged back into active campaigning on Tuesday while President Barack Obama stayed close to the White House, rival candidates calibrating their responses to superstorm Sandy and the misery it inflicted on millions.

In a close race with one week to run, both men appealed for donations — for relief agencies rather than their own campaign treasuries.

Looking Back at Hurricane Sandy's Devastation

"This is a tough time for millions of people ... But America is tougher," the president said during a brief visit to the American Red Cross, where he warned of more storm damage to come yet sought to reassure victims. He said he wanted "no bureaucracy, no red tape" to interfere with recovery, and suggested the military might be able to help in view of the enormity of the damage.

Election 2012: A Look Back

Romney, too, spoke of concern for storm victims. "A lot of people hurting this morning," he told several hundred supporters who were collecting supplies for victims of the storm that ravaged parts of the Eastern Seaboard on Monday before moving inland overnight. "We're looking for all the help we can get for all the families that need."

The race for the White House was hardly on hold.

Both campaigns pushed their supporters to vote early, and millions of them did.

In Florida, election officials said more than 2.2 million ballots had been cast by absentee mail-in ballots or in person as of Monday night, a total approaching 20 percent of the electorate.

Ubiquitous polls offered little clarity. Many showed a statistically insignificant 1 or 2 percentage-point margin for one candidate or the other, and individual battleground state surveys were close.

That made the storm-driven interlude even more delicate as the two campaigns sought to execute late-campaign strategies without appearing insensitive to the enormity of the loss in New York, New Jersey and elsewhere.

With the incumbency at his disposal, Obama received a briefing on the storm, presided over a telephone conference call with governors and mayors from affected areas and arranged a trip Wednesday to New Jersey, where Republican Gov. Chris Christie has praised his management of the storm disaster.

Obama's limousine ride to the Red Cross took him only a few blocks from the White House, but he was assured of national news coverage when he spoke.

Romney, too, was in public during the day, although his appearance was a blend of the political and the nonpartisan.

He didn't mention Obama in his brief remarks, but aides showed a campaign video on large screens inside the arena before he arrived. "I will devote every waking hour of my energy to getting America strong again. That's what an American president has to do," he says in it.

Standing in front of tables where campaign volunteers had neatly lined up toothpaste, diapers, canned food and fleece blankets, he said: "We have heavy hearts as you know with all the suffering going on in a major part of our country," he said, referring to the storm. Afterwards, he loaded relief supplies into a waiting truck.

Romney has said he believes state and local governments should have primary responsibility for emergency cleanup, and he refused Tuesday to answer repeated questions from reporters about how he would run the Federal Emergency Management Agency if he wins the election.

Asked about federal aid to help recover and rebuild from Sandy, Romney spokeswoman Amanda Henneberg said: "A Romney-Ryan administration will always ensure that disaster funding is there for those in need. Period."

Romney later flew to Florida, where he is slated to appear at three campaign rallies on Wednesday before moving on to other battleground states in the final days of the campaign.